I was able to retrieve your post and have read it . . . and cried.
First of all, my condolences to you and your family on the loss of your mother. Please don't apologize for the length of your post. You've written exactly what you should. Your Dr. is right; talking about your feelings of anxiety helps. It's not easy to talk about chronic anxiety to people who've never experienced it. Here, we can relate to everything you've written.
I understand what you are going through. There is no time limit to the grieving process. You've experienced the trauma of your mother's diagnosis and passing in such a short period of time. I can only imagine your desperate struggle to help. Your Dad's feelings are not uncommon and I commend you for your understanding. He's also grieving and needs time also. You are his family and he will miss all of you as time passes. You've done all that a good son can do and I'm sure you will see more of him in his own time. Be as patient as you've been and look towards your wife and children for the mutual comfort you need. Yes, you are the nurturing kind, and your family is there for you.
I can also understand you may have feelings of guilt also. Your mother's eyes held so much for you. Please know that she may not have been sad that you did not tell her, but her sadness may have been for the thought of not being there for all of you. I write this only because my feelings are such as I am also a mother and grandmother and I couldn't bear to leave them. Such is the nature of the maternal instinct.
It may be time for a change. For starters, a little trip away from home with your family can help. Talk with your wife about your feelings. She may want to help you make some changes to your lifestyle. A change of diet can help with your blood pressure as well as anxiety. Exercise at home, jogging or at the gym helps to alleviate depression. Relaxation in any form is crucial to help reduce stress. Read around the site and see what changes other people have undertaken to ease their anxiety. Taking care of yourself is the key to a healthy anxiety-free life. It may not be easy at first and may take some time, but it's worth the energy and time.
Continue with your psychotherapy. Ask your therapist about different treatments available. Keep coming back to post and blog. This is an excellent means of supplementing therapy, gaining advice and adding to your network of support. There are many caring people here who have gone through similar situations, myself included. We care about how you're doing and want to help . . . hugs